In general, an observation satellite, or a remote sensing satellite, located on the geostationary orbit may employ the image navigation and registration (INR) scheme to correct a geometric distortion in a satellite image for providing accurate observation information. A satellite INR system may model an error-caused process with respect to a pixel position in an image and correct the error such that the error is maintained to be within an allowable range. For example, the attitude, orbit, and satellite payload misalignment errors may be the source of the errors and the targets to be corrected.
In the INR system, the reference point selection may affect the overall system configuration, the design of interfaces between the subsystems, and various other aspects such as the developmental composition, costs, a future operation plan, and the like. When the INR system for geostationary orbital 3-axis satellite was first developed in the early 1990s, the initial INR system has employed the reference points composed of both landmarks and stars (GOES-I to M satellites in the US). This INR system using the combination of the landmarks and the starts has been continually applied to GOES-N to P in the US and MASAT-1R in Japan. As the reference point used for geometric correction, the landmark is sensitive to both the orbit and the attitude of a satellite and thus, may be useful for correcting both the orbit and the attitude. In contrast, the star is sensitive to only the attitude of the satellite and thus, may be useful for correcting the attitude. Prior to the era when the landmark acquisition process was automated, it has depended on a manual operation by an operator and thus, the number of effective landmarks that could be used in a single processing was relatively small. For this reason, all available reference points may have been secured and used to increase accuracy in the correction. Also, to meet the requirement of a less than three minutes processing time delay or product latency, the correction may have been processed on board by directly moving the mirror inside of the on-board instrument (camera). In order to generate correction information for this purpose, all of the available reference points may have been secured and used. As for the star sensing method, to avoid the burden of paying royalties for the international patent, among other reasons, an INR system that uses landmarks without star sensing has been developed for, for example, the COMS satellite in Korea and the MTSAT-2 satellite in Japan.
In the US, for the GOES-R satellite following the GOES-P satellite the INR system that uses an on-board global positioning system (GPS) for the orbit estimation and determination has been designed and developed. Through this, a star-based INR system has been provided, instead of the INR system that uses the combination between the landmark and the star, which had been adopted in the previous GOES satellite heritage system. However, the star-based INR system has become available in the GOES-R satellite because the orbit determination system using the on-board GPS provides estimated orbit information with high accuracy. Therefore, there exists a certain limit in choosing and using the INR system that adopts only the star sensing for most geostationary remote sensing satellites.